Process for the manufacture of phosphorus and phosphoric acid



-duc1ng a phosphoric ac1d in a combination WILLIAM H. WAGGAMAN, OF WASHINGTON, DISTRICT OF COLUMBIA.

PROCESS FOR THE MANUFACTURE OF PHOSPHORUS PHOSPHORIC ACID.

inseam.

Ito Drawing.

Specification of Letters Patent.

Patented Mar. 23, 1920.

Application filed August 1, 1919. Serial No. 314,791.

(FILED UNDER THE ACT OF MARCH.3, 1883, 22 STAT. L, 625.)

To all whom it may concern:

Be it known that 1, WILLIAM H. WAG- GAMAN, a citizen of the United States; and an employee of the Department of Agriculture of the United States of America, residing at Washington, District of Columbia, whose post-ofiice address is Washington, District of Columbia, have invented a new and useful Process for the Manufacture of Phosphorus and Phosphoric Acid.

This application is made under the act of March 3, 1883, chapter-1453 (22 Stat. 625) and the invention herein described and claimed may be used by the Government of the- United States or any of its officers or employees in the prosecution of work for the Government, and any person in the United States without payment to me of any royalty thereon.

This invention relates to a process of problast and open hearth furnace, and has for its object to provide a method which will obtain this object when using natural phosphates more elliciently and economically than has been heretofore accomplished.

With these and other objects in view the invention consists in the novel combination of steps more fully hereinafter disclosed and particularly pointed out in the claims.

' In order that the invention may be clearly understood and distinguished from the prior art it maybe said that it is well known that it has been proposed to produce phosphorus and phosphoricacid as by products in the manufacture of metallic .phosphids in the usual type of blast furnace. It is generallybelieved however that the com-" plete volatilization of phosphorus and phosphoric acid from mixtures of natural phosphates, silica and coke can be effected by the high temperature attainable only in the electric furnace. I have found however that under the proper conditions, 90

per cent. or more of the phosphoric acid insuch mixtures may be driven off at tempera tures readily obtained by burning such fuels as coal, coke, tar, oil and gas. The conditions under which a high yield of phos phorus and phosphoric acid may be obtained from such a mixture are as follows: (1) The ingredients must be very thoroughly ground and intimately mixed; (2) the particles of the mixture must be held in close contact to facilitate the reactions which take place at high temperatures; (3) reducing conditions must be maintained in the mass until a smelting temperature is obtained; (if) after a slag is produced it must be maintained in a molten state in order to complete the reactions and facilitate the evolution of the balance of the phosphorus and phosphoric acid contained therein.

I have found that all of these conditions may be fulfilled as follows:

The finely ground charge of a natural phosphate, silica and coke or other reducing agent is intimately mixed in some suit-' able manner with a binding material which. may either be added from some outside source or may be already contained in the mixture (as is the case with much of the run of mine phosphate ofFlorida which usually contains suflicientsoft phosphate or clay-like material to act as a binder when the material is moistenedand compressed). The mixture containing the binding material is then passed through a briqueting ma chine of some well known design, such as the Belgian roll type of press, and satisfac- 'tory briquets are produced which can be. readily handled without breakage and which will maintain their form and shape until heated to a smelting temperature. These briquets are then charged in at the top of a combination blast and open hearth furnace which is heated by means of either tar, oil, gas or powdered coal burners. The temperature attained in such a furnace is soon suffic'ient to form a glaze or coating on the surface of the briquet which protects the coke or other reducing agent in the interior of the briquets from oxidizing influences until the mixture in the interior of said briquets has reacted to form a fusible slag. The close contact of the particles in the briquets facilitates the reactions which bring about the formation of a fusible silicate and thedevolution of phosphorus and phosphoric aci l The slag formed then drips from the lower end of the furnace shaft into a slag chamber pro ided with an elongated health over which the flames and hot gases from the combustion of the fuel are continually sweeping. The heat absorbed from these flames renders the slag more fluid and mainance of the a finely ground tains it in a molten condition until the balphosphoric acid therein is evolved.

The phosphorus, phorphoric acid and gases of combustion are continually withdrawn from the slag chamber and furnace shaft by means of a suitable opening or flue in the upper part of said shaft, and the slag which is largely exhausted of its phosphate content is run out of, suitable tap holes in the sides of the slag chamber.

From the foregoing operation and advantages of the herein described process will be apparent to those skilled in the art without further description and it will be understood that various changes in the minor details of operation and manipulation may be resorted to without departing from the spirit or sacrificing anyI of the advantages of the invention.

aving now described my invention I claim:

1. A process of producing phosphorus and phosphoric acid from. natural phosphates which consists in intimately mixing charge of natural phosphates, suitable binder, pressing said mixture into briquets, charging said briquets into a furnace, volatilizing phosphorus and phosphoric acid from the phosphate minerals contained in said briquets while converting them into a molten mass by means of burning fuel, and driving off and subsequently collecting the balance of the it is thought that the silica, and a solid fuel, with some phosphorus and phosphoric acid contained 1n the slag by playing flames and hot gases from burning fuel over the surface of said slag, substantially as described. 7

2. A process of producing phosphorus and phosphoric acid from natural phosphates which consists in intimately mixing finely ground natural phosphates, silica, and a solid fuel, with some suitable binder, maintaining close contact between the particles of said mixture by pressing it into briquets, charging said briquets into a furnace, maintaining reducing conditions within said briquets by rapidly heating them to a point where a glaze or coating relatively impervious to oxidizing gases forms over their surface, volatilizing phosphorus and phosphoric acid from the phosphate minerals contained in said briquets while converting them into a molten mass by means of burning fuel, and driving off and subsequently collecting the balance of the phosphorus and phosphoric acid contained in the slag by playing flames and hot gases from burning fuel over the surface of said slag, substantially as described.

In testimony whereof I aflix my signature in the presence of two Witnesses.

WILLIAM H. WAGGAMAN.

Witnesses:

JAcoB W. BOMBOY, WILLIAM H. FRY. 

